Handbook of the Behavioral Neurobiology of Serotonin, Second Edition, builds on the success of the first edition by continuing to provide a detailed and comprehensive overview of the many facets of behavioral serotonin research. The text expands on the two key topics, behavioral control (sensory processing, ultrasonic vocalization, and melatonin and sleep control) and psychiatric disorders, including its role on psychostimulant abuse and addiction. The new edition includes two new sections on the serotonin systems interactions and the involvement of serotonin in neurological disorders and associated treatment. Serotonin is a major neurotransmitters in the serotonergic system which one of the best studied and understood transmitter systems. Both are critically involved in the organization of all behaviors and in the regulation of emotion and mood.